A screen printing apparatus is mounted to a component mounting line together with a component mounting apparatus or an attachment apparatus to perform a screen printing using cream solder or conductive paste to a substrate introduced from the upstream side and to discharge the substrate to an apparatus provided on the downstream side of the component mounting line. In general, the screen printing apparatus is disposed on the upstream side of the component mounting apparatus and the substrate subjected to the screen printing is directly or indirectly transferred from a substrate discharge portion of the screen printing apparatus to a substrate transportation path of the component mounting apparatus. The component mounting apparatus mounts components to the substrate introduced from the screen printing apparatus, and discharges the substrate to an apparatus provided on the downstream side via the substrate transportation path.
Incidentally, among recent component mounting apparatuses, there is a component mounting apparatus in which two parallel substrate transportation paths are provided and the component mounting operation is simultaneously carried out by two component mounting lines via the two substrate transportation paths. Likewise, when the component mounting apparatus includes two substrate transportation paths, the substrate discharged from the substrate discharge portion of the screen printing apparatus is distributed to the two substrate transportation paths of the component mounting apparatus by a substrate distributing device provided between the component mounting apparatus and the screen printing apparatus (JP-A-H04-129630).
However, in the component mounting apparatus having the two component mounting lines, the component mounting operation may be carried out in the different types of substrates (including a case carried out in the same type of substrates but on different surfaces in addition to a case carried out the different types of the substrates) at the same time as well as the component mounting operation carried out in the same type of substrates. In this case, since the screen printing apparatus cannot continuously perform the screen printing to the different types of substrates, it is necessary to provide two screen printing apparatuses in parallel to each other at a position on the upstream side of the component mounting apparatus. However, since the interval between the two substrate transportation paths constituting the component mounting apparatus is very narrow, it is very difficult to provide two screen printing apparatuses in parallel so that the substrate discharge portions of the screen printing apparatuses are opposed to the two substrate transportation paths of the component mounting apparatus.
Additionally, instead of the above-described technique, it may be supposed that two types of mask plates are provided at a position above one substrate transportation path constituting the screen printing apparatus so as to be disposed in a line in a direction in which the substrate transportation path extends (JP-A-2000-168040), thereby performing the different types of screen printings to the substrate on the substrate transportation path. However, since the different types of masks are provided in serial to the one substrate transportation path of the screen printing apparatus, it is necessary to provide a complex substrate supply system to the substrate transportation path so as to supply the different substrates alternatively or once in several substrates.